Example

> A = rand(3,3)
 A =
    0.965      0.239      0.415  
    0.883       0.54      0.625  
    0.858     0.0691     0.0172  
> L = hess(A)
   h            p            
> L.h
 h =
    0.965     -0.461      0.132  
    -1.23      0.633    -0.0267  
        0       0.53     -0.076  
> L.p
 p =
        1          0          0  
        0     -0.717     -0.697  
        0     -0.697      0.717  
> L.p*L.h*L.p'
    0.965      0.239      0.415  
    0.883       0.54      0.625  
    0.858     0.0691     0.0172